icuSources/i18n/strmatch.h

   1 /*
   2  * Copyright (C) 2001-2004, International Business Machines Corporation
   3  * and others. All Rights Reserved.
   4  **********************************************************************
   5  *   Date        Name        Description
   6  *   07/23/01    aliu        Creation.
   7  **********************************************************************
   8  */
   9 #ifndef STRMATCH_H
  10 #define STRMATCH_H
  11
  12 #include "unicode/utypes.h"
  13
  14 #if !UCONFIG_NO_TRANSLITERATION
  15
  16 #include "unicode/unistr.h"
  17 #include "unicode/unifunct.h"
  18 #include "unicode/unimatch.h"
  19 #include "unicode/unirepl.h"
  20
  21 U_NAMESPACE_BEGIN
  22
  23 class TransliterationRuleData;
  24
  25 /**
  26  * An object that matches a fixed input string, implementing the
  27  * UnicodeMatcher API.  This object also implements the
  28  * UnicodeReplacer API, allowing it to emit the matched text as
  29  * output.  Since the match text may contain flexible match elements,
  30  * such as UnicodeSets, the emitted text is not the match pattern, but
  31  * instead a substring of the actual matched text.  Following
  32  * convention, the output text is the leftmost match seen up to this
  33  * point.
  34  *
  35  * A StringMatcher may represent a segment, in which case it has a
  36  * positive segment number.  This affects how the matcher converts
  37  * itself to a pattern but does not otherwise affect its function.
  38  *
  39  * A StringMatcher that is not a segment should not be used as a
  40  * UnicodeReplacer.
  41  */
  42 class StringMatcher : public UnicodeFunctor, public UnicodeMatcher, public UnicodeReplacer {
  43
  44  public:
  45
  46     /**
  47      * Construct a matcher that matches the given pattern string.
  48      * @param string the pattern to be matched, possibly containing
  49      * stand-ins that represent nested UnicodeMatcher objects.
  50      * @param start inclusive start index of text to be replaced
  51      * @param limit exclusive end index of text to be replaced;
  52      * must be greater than or equal to start
  53      * @param segmentNum the segment number from 1..n, or 0 if this is
  54      * not a segment.
  55      * @param data context object mapping stand-ins to
  56      * UnicodeMatcher objects.
  57      */
  58     StringMatcher(const UnicodeString& string,
  59                   int32_t start,
  60                   int32_t limit,
  61                   int32_t segmentNum,
  62                   const TransliterationRuleData& data);
  63
  64     /**
  65      * Copy constructor
  66      * @param o  the object to be copied.
  67      */
  68     StringMatcher(const StringMatcher& o);
  69
  70     /**
  71      * Destructor
  72      */
  73     virtual ~StringMatcher();
  74
  75     /**
  76      * Implement UnicodeFunctor
  77      * @return a copy of the object.
  78      */
  79     virtual UnicodeFunctor* clone() const;
  80
  81     /**
  82      * UnicodeFunctor API.  Cast 'this' to a UnicodeMatcher* pointer
  83      * and return the pointer.
  84      * @return the UnicodeMatcher point.
  85      */
  86     virtual UnicodeMatcher* toMatcher() const;
  87
  88     /**
  89      * UnicodeFunctor API.  Cast 'this' to a UnicodeReplacer* pointer
  90      * and return the pointer.
  91      * @return the UnicodeReplacer pointer.
  92      */
  93     virtual UnicodeReplacer* toReplacer() const;
  94
  95     /**
  96      * Implement UnicodeMatcher
  97      * @param text the text to be matched
  98      * @param offset on input, the index into text at which to begin
  99      * matching.  On output, the limit of the matched text.  The
 100      * number of matched characters is the output value of offset
 101      * minus the input value.  Offset should always point to the
 102      * HIGH SURROGATE (leading code unit) of a pair of surrogates,
 103      * both on entry and upon return.
 104      * @param limit the limit index of text to be matched.  Greater
 105      * than offset for a forward direction match, less than offset for
 106      * a backward direction match.  The last character to be
 107      * considered for matching will be text.charAt(limit-1) in the
 108      * forward direction or text.charAt(limit+1) in the backward
 109      * direction.
 110      * @param incremental  if TRUE, then assume further characters may
 111      * be inserted at limit and check for partial matching.  Otherwise
 112      * assume the text as given is complete.
 113      * @return a match degree value indicating a full match, a partial
 114      * match, or a mismatch.  If incremental is FALSE then
 115      * U_PARTIAL_MATCH should never be returned.
 116      */
 117     virtual UMatchDegree matches(const Replaceable& text,
 118                                  int32_t& offset,
 119                                  int32_t limit,
 120                                  UBool incremental);
 121
 122     /**
 123      * Implement UnicodeMatcher
 124      * @param result            Output param to receive the pattern.
 125      * @param escapeUnprintable if True then escape the unprintable characters.
 126      * @return                  A reference to 'result'.
 127      */
 128     virtual UnicodeString& toPattern(UnicodeString& result,
 129                                      UBool escapeUnprintable = FALSE) const;
 130
 131     /**
 132      * Implement UnicodeMatcher
 133      * Returns TRUE if this matcher will match a character c, where c
 134      * & 0xFF == v, at offset, in the forward direction (with limit >
 135      * offset).  This is used by <tt>RuleBasedTransliterator</tt> for
 136      * indexing.
 137      * @param v    the given value
 138      * @return     TRUE if this matcher will match a character c,
 139      *             where c & 0xFF == v
 140      */
 141     virtual UBool matchesIndexValue(uint8_t v) const;
 142
 143     /**
 144      * Implement UnicodeMatcher
 145      */
 146     virtual void addMatchSetTo(UnicodeSet& toUnionTo) const;
 147
 148     /**
 149      * Implement UnicodeFunctor
 150      */
 151     virtual void setData(const TransliterationRuleData*);
 152
 153     /**
 154      * Replace characters in 'text' from 'start' to 'limit' with the
 155      * output text of this object.  Update the 'cursor' parameter to
 156      * give the cursor position and return the length of the
 157      * replacement text.
 158      *
 159      * @param text the text to be matched
 160      * @param start inclusive start index of text to be replaced
 161      * @param limit exclusive end index of text to be replaced;
 162      * must be greater than or equal to start
 163      * @param cursor output parameter for the cursor position.
 164      * Not all replacer objects will update this, but in a complete
 165      * tree of replacer objects, representing the entire output side
 166      * of a transliteration rule, at least one must update it.
 167      * @return the number of 16-bit code units in the text replacing
 168      * the characters at offsets start..(limit-1) in text
 169      */
 170     virtual int32_t replace(Replaceable& text,
 171                             int32_t start,
 172                             int32_t limit,
 173                             int32_t& cursor);
 174
 175     /**
 176      * Returns a string representation of this replacer.  If the
 177      * result of calling this function is passed to the appropriate
 178      * parser, typically TransliteratorParser, it will produce another
 179      * replacer that is equal to this one.
 180      * @param result the string to receive the pattern.  Previous
 181      * contents will be deleted.
 182      * @param escapeUnprintable if TRUE then convert unprintable
 183      * character to their hex escape representations, \\uxxxx or
 184      * \\Uxxxxxxxx.  Unprintable characters are defined by
 185      * Utility.isUnprintable().
 186      * @return a reference to 'result'.
 187      */
 188     virtual UnicodeString& toReplacerPattern(UnicodeString& result,
 189                                              UBool escapeUnprintable) const;
 190
 191     /**
 192      * Remove any match data.  This must be called before performing a
 193      * set of matches with this segment.
 194      */
 195     void resetMatch();
 196
 197     /**
 198      * ICU "poor man's RTTI", returns a UClassID for the actual class.
 199      *
 200      * @draft ICU 2.2
 201      */
 202     virtual UClassID getDynamicClassID() const;
 203
 204     /**
 205      * ICU "poor man's RTTI", returns a UClassID for this class.
 206      *
 207      * @draft ICU 2.2
 208      */
 209     static UClassID U_EXPORT2 getStaticClassID();
 210
 211     /**
 212      * Union the set of all characters that may output by this object
 213      * into the given set.
 214      * @param toUnionTo the set into which to union the output characters
 215      */
 216     virtual void addReplacementSetTo(UnicodeSet& toUnionTo) const;
 217
 218  private:
 219
 220     /**
 221      * The text to be matched.
 222      */
 223     UnicodeString pattern;
 224
 225     /**
 226      * Context object that maps stand-ins to matcher and replacer
 227      * objects.
 228      */
 229     const TransliterationRuleData* data;
 230
 231     /**
 232      * The segment number, 1-based, or 0 if not a segment.
 233      */
 234     int32_t segmentNumber;
 235
 236     /**
 237      * Start offset, in the match text, of the <em>rightmost</em>
 238      * match.
 239      */
 240     int32_t matchStart;
 241
 242     /**
 243      * Limit offset, in the match text, of the <em>rightmost</em>
 244      * match.
 245      */
 246     int32_t matchLimit;
 247
 248 };
 249
 250 U_NAMESPACE_END
 251
 252 #endif /* #if !UCONFIG_NO_TRANSLITERATION */
 253
 254 #endif